Lubricating oil composition

ABSTRACT

Compounds having the formula: ##STR1## wherein: a. each of R, R 2  and R 4  when taken singly is a hydrogen atom, an alkyl group containing from 1 to about 15 carbon atoms, an aryl group containing from 6 to about 15 carbon atoms or a cycloalkyl group containing from 4 to about 10 carbon atoms; 
     b. each of R 1  and R 3  when taken singly is a hydrogen atom, an alkyl group containing from 1 to about 15 carbon atoms; an aryl group containing from 6 to about 15 carbon atoms; a cycloalkyl group containing from 4 to about 10 carbon atoms or an alkenyl group containing from 2 to about 10 carbon atoms or R 1  and R 3  taken together form the group --CHYCY═CY-- in which Y is a hydrogen atom or a methyl group or R 1  together with R 2  form an alkylidene group containing from 1 to about 6 carbon atoms; 
     c. R 5  is a hydrogen atom or an alkyl group containing from 1 to about 15 carbon atoms; 
     d. R 6  is an organic radical selected from an alkyl group, an alkenyl group, an aryl group or an aralkyl group in which the alkyl or alkenyl groups contain up to 32 carbon atoms and the aryl or aralkyl groups contain up to 15 carbon atoms each; and 
     e. R 7  is hydrogen or an organic radical selected from an alkyl group or alkenyl group, an aryl or aralkyl group in which the alkyl or alkenyl groups contain up to 32 carbon atoms and the aryl or aralkyl groups contain up to 15 carbon atoms each, 
     are effective antiwear and antioxidant additives in lubricating oils.

This application is a division of application ser. no. 189,101, filedMay 2, 1988 now U.S. Pat. No. 4,876,375.

BACKGROUND OF THE INVENTION

This invention relates to dithiocarbamyl substituted norbornyl productshaving utility as lubricant additives and lubricating compositionscontaining them. The invention also relates to a process for preparingsuch products.

Additives are conventionally added to lubricating oils to improve theirproperties. Antiwear additives used in the past include compounds suchas zinc dialkyldithiophosphates, sulfurized sperm oil, and the like.Antioxidant additives used in the past include sulfurized oil-solubleorganic compounds, such as wax sulfides and polysulfides, sulfurizedolefins, sulfurized fatty acid esters, and sulfurized olefin esters, aswell as oil soluble phenolic and aromatic amine antioxidants.

It has now been found that certain dithiocarbamyl substituted norbornylproducts are very effective antiwear and anti oxidant additives inlubricating compositions such as crankcase lubricants.

DETAILED DESCRIPTION OF THE INVENTION

Accordingly, in one aspect of the present invention there is provided anantiwear and antioxidant compound having the general formula: ##STR2##wherein: a. each of R, R² and R⁴ when taken singly is a hydrogen atom,an alkyl group containing from 1 to about 15 carbon atoms, an aryl groupcontaining from 6 to about 15 carbon atoms or a cycloalkyl groupcontaining from 4 to about 10 carbon atoms;

b. each of R¹ and R³ when taken singly is a hydrogen atom, an alkylgroup containing from 1 to about 15 carbon atoms; an aryl groupcontaining from 6 to about 15 carbon atoms; a cycloalkyl groupcontaining from 4 to about 10 carbon atoms or an alkenyl groupcontaining from 2 to about 10 carbon atoms or R¹ and R³ taken togetherform the group --CHYCY═CY-- in which Y is a hydrogen atom or a methylgroup or R¹ together with R² form an alkylidene group containing from 1to about 6 carbon atoms;

c. R⁵ is a hydrogen atom or an alkyl group containing from 1 to about 15carbon atoms;

d. R⁶ is an organic radical selected from an alkyl group, an alkenylgroup, an aryl group or an aralkyl group in which the alkyl or alkenylgroups contain up to 32 carbon atoms and the aryl or aralkyl groupscontain up to 15 carbon atoms each; and

e. R⁷ is hydrogen or an organic radical selected from an alkyl group oralkenyl group, an aryl or aralkyl group in which the alkyl or alkenylgroups contain up to 32 carbon atoms and the aryl or aralkyl groupscontain up to 15 carbon atoms each.

The additives of the invention are readily prepared by reacting aprimary or secondary amine, i.e. compounds having one or more primary orsecondary amino groups, preferably primary and secondary monoamines ofthe general formula:

    R.sup.6 --NH--R.sup.7

where R⁶ and R⁷ are as defined above with carbon disulfide and acompound having the general formula: ##STR3## wherein R, R¹, R², R³, R⁴and R⁵ are as hereinbefore defined.

Specific examples of compound (B) which may be used in the practice ofthe present invention include 5-vinylnorbornene, dicyclopentadiene andnorbornylene of which dicyclopentadiene and norbornylene are preferred.

As stated above, the amine reactants of the present invention can berepresented by the formula:

    R.sup.6 --NH--R.sup.7

where R⁶ is an organic radical, e.g. an alkyl group, an alkenyl group,an aryl group, or an aralkyl group. The alkyl or alkenyl groups cancontain up to 32 carbon atoms, preferably up to 12 carbon atoms, and thearyl or aralkyl groups, which include a benzene or a naphthalene nucleussubstituted by alkyl radicals or aryl or aralkyl radicals, preferablycontain up to 15 carbon atoms each. The alkyl or alkenyl groups can beacyclic and of straight chain or branched structure, or they may bealicyclic. The R⁶ group may be interrupted by a hetero atom linkage,such as O or S, and may contain one or more primary or secondary aminogroups. In the foregoing formula, R⁷ can be hydrogen, but it may be analkyl, alkenyl, aryl or aralkyl group, as defined for R⁶, and may be thesame as R⁶ or it may be different from R⁶ in a given compound. When R⁶and R⁷ are alkyl groups, they may be joined together to form aheterocyclic link with the nitrogen atom to which they are attached. R⁶and R⁷ may also be substituted by non-interfering groups such as alkoxy,halo and amido groups, and the like.

Specific examples of suitable amine reactants which can be used in thepractice of the present invention include methylamine, ethylamine,propylamine, isopropylamine, n-butylamine, sec-butylamine,isobutylamine, pentylamine, hexylamine, cyclohexylamine, heptylamine,octylamine, dodecylamine, octadecylamine, eicosylamine,triacontanylamine, benzylamine, chlorobenzylamine, nitrobenzylamine,2-ethoxyethylamine, 4-carbomethoxyhexylamine, dimethylamine,diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine,di-sec-butylamine, diisobutylamine, di-tert-butylamine, dipentylamine,dihexylamine, dioctylamine, dieicosylamine, ditriacontanylamine,N-methylethylamine, N-methylpropylamine, N-methyloctadecylamine,N-ethylhexylamine, N-ethyldodecylamine, N-propyldodecylamine, aniline,toluidine (o-, m-, or p-), 2,4-xylidine, 3,4-xylidine, 2,5-xylidine,4-ethylaniline, 3-propylaniline, 1,3-diamino benzene,4,4'-diamino-diphenyl methane, p-chloro aniline, 2,6-diamino toluene,4,4'-diaminodiphenyl, 2,4,4'-triamino diphenyl ether, 2,6-diaminonaphthalene, 1,5-diamino-2-methylpentane, phenylethyl amine, piperidine,morpholine, piperazine, glycine, 2-amino ethyl ether, 2-amino ethylsulfide, and the like. The preferred amino compounds are lower alkylsecondary amines wherein each of R⁶ and R⁷ as described above have up toabout 12 carbon atoms.

In the process of the invention, equal mole quantities of the reactantsare used although a slight excess of carbon disulfide may be used, ifdesired, in order to compensate for any loss of carbon disulfide whichcan occur during the course of the reaction through volatilization toinsure maximum yield of product. The reaction can be convenientlycarried out by merely mixing the reactants and heating. However, it ispreferable to add the amine reactant slowly, in a dropwise fashion, to areaction vessel containing a mixture of the carbon disulfide andcompound (B) reactants in order to avoid unwanted amine salt formationwhich can occur when all of the carbon disulfide reactant is contactedwith all of the amine reactant simultaneously.

In general, a reaction temperature should be used which is high enoughto promote the reaction at a reasonable rate, but not so high as tocause decomposition. A useful range is from about 30-100° C. A moreuseful range is from about 50-90° C.

The reaction can be carried out in an inert atmosphere if desired, butthe use of an inert atmosphere above the reaction mixture is notrequired.

The reaction should be carried out for a time sufficient to form asubstantial amount of product. This is usually accomplished from 0.5 to12 hours. A more useful time range is from about 2 to 4 hours.

Thus, in accordance with another aspect of the invention, there isprovided a process for preparing an oil-soluble compound having theformula: ##STR4## wherein: a. each of R, R² and R⁴ when taken singly isa hydrogen atom, an alkyl group containing from 1 to about 15 carbonatoms, an aryl group containing from 6 to about 15 carbon atoms or acycloalkyl group containing from 4 to about 10 carbon atoms;

b. each of R¹ and R³ when taken singly is a hydrogen atom, an alkylgroup containing from 1 to about 15 carbon atoms; an aryl groupcontaining from 6 to about 15 carbon atoms; a cycloalkyl groupcontaining from 4 to about 10 carbon atoms or an alkenyl groupcontaining from 2 to about 10 carbon atoms or R¹ and R³ taken togetherform the group --CHYCY═CY-- in which Y is a hydrogen atom or a methylgroup or R¹ together with R² form an alkylidene group containing from 1to about 6 carbon atoms;

c. R⁵ is a hydrogen atom or an alkyl group containing from 1 to about 15carbon atoms;

d. R⁶ is an organic radical selected from an alkyl group, an alkenylgroup, an aryl group or an aralkyl group in which the alkyl or alkenylgroups contain up to 32 carbon atoms and the aryl or aralkyl groupscontain up to 15 carbon atoms each; and

e. R⁷ is hydrogen or an organic radical selected from an alkyl group oralkenyl group, an aryl or aralkyl group in which the alkyl or alkenylgroups contain up to 32 carbon atoms and the aryl or aralkyl groupscontain up to 15 carbon atoms each

by reacting a compound having the general formula: ##STR5## wherein R,R¹, R², R³, R⁴ and R⁵ are as hereinbefore defined with carbon disulfideand an amine having the general formula:

    R.sup.6 --NH--R.sup.7

where R⁶ is an organic radical selected from an alkyl group, an alkenylgroup, an aryl group or an aralkyl group in which the alkyl or alkenylgroups contain up to 32 carbon atoms and the aryl or aralkyl groupscontain up to 15 carbon atoms each; and, R⁷ is hydrogen or an organicradical selected from an alkyl group or alkenyl group, an aryl oraralkyl group in which the alkyl or alkenyl groups contain up to 32carbon atoms and the aryl or aralkyl groups contain up to 15 carbonatoms each.

Preferably, the lubricating compositions of the present inventioncomprise from 0.1% to 10%, more preferably, 0.25% to 5% by weight of theoil-soluble products of foregoing formula (A) and the lubricating oilmay be any of the well-known mineral or synthetic oils of appropriateviscosity characteristics.

It will be understood that the lubricating compositions of the presentinvention may also contain, if desired, conventional lubricant additivessuch as ancillary antioxidants and antiwear additives (preferablyashless), corrosion inhibitors, dispersants, detergents, thickeners,pour-point depressants and viscosity index improvers.

Hence, in accordance with another aspect of the present invention thereis provided a lubricating composition containing a major amount oflubricating oil and a minor antiwear-antioxidant amount of a compoundhaving the general formula: ##STR6## wherein: a. each of R, R² and R⁴when taken singly is a hydrogen atom, an alkyl group containing from 1to about 15 carbon atoms, an aryl group containing from 6 to 15 carbonatoms or a cycloalkyl group containing from 4 to about 10 carbon atoms;

b. each of R1 and P. when taken singly is a hydrogen atom, an alkylgroup containing from 1 to about 15 carbon atoms; an aryl groupcontaining from 6 to about 15 carbon atoms; a cycloalkyl groupcontaining from 4 to about 10 carbon atoms or an alkenyl groupcontaining from 2 to about 10 carbon atoms or R¹ and R³ taken togetherform the group --CHYCY═CY-- in which Y is a hydrogen atom or a methylgroup or R¹ together with R² form an alkylidene group containing from 1to about 6 carbon atoms;

c. R⁵ is a hydrogen atom or an alkyl group containing from 1 to about 15carbon atoms;

d. R⁶ is an organic radical selected from an alkyl group, an alkenylgroup, an aryl group or an aralkyl group in which the alkyl or alkenylgroups contain up to 32 carbon atoms and the aryl or aralkyl groupscontain up to 15 carbon atoms each; and

e. R⁷ is hydrogen or an organic radical selected from an alkyl group oralkenyl group, an aryl or aralkyl group in which the alkyl or alkenylgroups contain up to 32 carbon atoms and the aryl or aralkyl groupscontain up to 15 carbon atoms each.

The additives of the present invention may also be conveniently preparedas a concentrate consisting of a concentrated solution of a major amountof the additives and a minor amount of a mineral or syntheticlubricating oil, or as an additive package consisting of a concentratedsolution in mineral oil or synthetic oil of a major amount of acombination of the additives with one or more conventional additives.Such concentrates and packages are frequently very convenient forms inwhich to handle and transport additives and are diluted with furtherquantities of oil, and optionally blended with further additives, beforeuse.

Thus, in accordance with a further aspect of the invention, there isprovided a solution comprising a major amount of one or more compoundshaving the formula (A) and a minor amount of a lubricating oil. One ormore conventional additives may be combined with the compounds offormula (A).

The following examples serve to illustrate the manner in which theantiwear and antioxidant additives are prepared but not to limit in anyrespect the scope of the invention claimed.

EXAMPLE I

To a 500 milliliter reaction vessel equipped with a stirrer, thermometerand condenser was added 37.6 grams (0.4 mole) of norbornylene and 38.0grams (0.5 mole) of carbon disulfide and the mixture was heatedgradually to 80° C. Beginning at 35° C., dibutylamine (51.6 grams; 0.4mole) was added dropwise over a period of 30 minutes. After addition ofthe amine, the reaction mixture was maintained at 80° C. for 1.5 hours.Vacuum was applied for 30 minutes to strip off volatiles and theresulting product was dissolved in heptane and the heptane solution waswashed twice with water, once with 10% aqueous sodium hydroxide, oncewith dilute hydrochloric acid and once again with water. The solvent wasremoved under vacuum after drying over anhydrous Na₂ SO₄. A dark redliquid (95.6 grams) was obtained. Analysis by NMR served to identify theproduct as norbornyl dibutyldithiocarbamate.

EXAMPLE II

To a 500 milliliter reaction vessel equipped with a stirrer, thermometerand condenser was added 68.6 grams (0.52 mole) of dicyclopentadiene and44.9 grams (0.59 mole) of carbon disulfide and the mixture was heatedgently. At 38-40° C., addition of dibutylamine was started. Anexothermic reaction occurred and the temperature gradually rose to 90°C. Heating was stopped at 80° C. The addition of amine (62.1 grams; 0.52mole) was completed in 45 minutes. The resulting mixture was held at 80°C. for one hour. Vacuum was then applied for 30 minutes to strip offvolatiles. The resulting product was dissolved in heptane and thesolution was washed once each with water, dilute hydrochloric acid, 5.0%aqueous sodium hydroxide, dilute hydrochloric acid and water. Theheptane solution was then dried over anhydrous Na₂ SO₄. After removal ofsolvent under vacuum there remained 141.8 grams of a dark orange liquidreaction product.

The antiwear properties of the lubricating oil compositions of thepresent invention were determined in a 4-Ball Wear Test. This test isconducted in a device comprising four steel balls, three of which are incontact with each other in one plane in a fixed triangular position anda reservoir containing the test sample. The fourth ball is above and incontact with the other three. In conducting the test, the upper ball isrotated while it is pressed against the other three balls while pressureis applied by weight and lever arms. The diameter of the scar on thethree lower balls is measured by means of a low-power microscope, andthe average diameter measured in two directions on each of three lowerballs is taken as a measure of the antiwear characteristics of the oil.A larger scar diameter means more wear. The balls were immersed in baselube oil containing the test additives. Applied load was 40 kg androtation was at 1800 rpm for 30 minutes at 130° F. Tests were conductedwith base oil alone (Exxon 80W-90 mineral oil) and with base oilcontaining 0.5 wt. % of the additives of Examples I and II. Results aregiven in the following table.

    ______________________________________                                                                 Scar                                                 Oil Formulation          Diameter (mm)                                        ______________________________________                                        Base Oil                 0.663                                                Base Oil + 0.5 wt. % additive (Example I)                                                              0.483                                                Base Oil + 0.5 wt. % additive (Example II)                                                             0.500                                                ______________________________________                                    

The results in the table show that lubricating oil containing theadditives of the present invention gave a scar diameter significantlyless than that of the base oil alone.

Hot Oil Oxidation Test were carried out to demonstrate the antioxidanteffectiveness of the present additives. In these tests, fully formulatedmineral lubricating oil samples were prepared both with and without theadditive. The oil is placed in a test cell together with 0.3 cubiccentimeter of a catalyst composition prepared by dissolving 6.65 gramsof ferric acetylacetonate and 0.6 gram of cupric acetylacetonate in 100grams of xylene This cell was heated to 160° C. and dry air blownthrough the heated oil for 48 hours at a rate of 10 liters/hour. Thepercent viscosity increase was measured at 40° C. The following resultswere obtained:

    ______________________________________                                        Additive            Percent Viscosity Increase                                ______________________________________                                        None                64.7                                                      Example I (0.26 wt. % based on                                                                    30.7                                                      total weight of the oil)                                                      Example II (0.26 wt. % based on                                                                   35.0                                                      total weight of the oil)                                                      ______________________________________                                    

These results demonstrate that the additive compounds of the inventionare effective antioxidants.

What is claimed:
 1. A lubricating composition containing a major amountof lubricating oil and a minor antiwear-antioxidant amount of anadditive compound having the general formula: ##STR7## wherein: a. eachof R, R² and R⁴ when taken singly is a hydrogen atom, an alkyl groupcontaining from 1 to about 15 carbon atoms, an aryl group containingfrom 6 to about 15 carbon atoms or a cycloalkyl group containing from 4to about 10 carbon atoms;b. each of R¹ and R³ when taken singly is ahydrogen atom, an alkyl group containing from 1 to about 15 carbonatoms; an aryl group containing from 6 to about 15 carbon atoms; acycloalkyl group containing from 4 to about 10 carbon atoms or analkenyl group containing from 2 to about 10 carbon atoms or R¹ and R³taken together form the group --CHYCY═CY-- in which Y is a hydrogen atomor a methyl group or R¹ together with R² form an alkylidene groupcontaining from 1 to about 6 carbon atoms; c. R⁵ is a hydrogen atom oran alkyl group containing from 1 to about 15 carbon atoms; d. R⁶ is anorganic radical selected from an alkyl group, an alkenyl group, an arylgroup or an aralkyl group in which the alkyl or alkenyl groups containup to 32 carbon atoms and the aryl or aralkyl groups contain up to 15carbon atoms each; and e. R⁷ is hydrogen or an organic radical selectedfrom an alkyl group or alkenyl group, an aryl or aralkyl group in whichthe alkyl or alkenyl groups contain up to 32 carbon atoms and the arylor aralkyl groups contain up to 15 carbon atoms each.
 2. A lubricatingcomposition of claim 1 containing an additive compound wherein R⁶ and R⁷are n-butyl and R, R¹, R², R³, R⁴ and R⁵ are hydrogen.
 3. A lubricatingcomposition of claim 1 containing an additive compound wherein R⁶ and R⁷are n-butyl, R, R², R⁴ and R⁵ are hydrogen and R¹ and R³ taken togetherform the group --CH₂ CH═CH--.
 4. A lubricating composition of claim 1containing an additive compound wherein R⁶ and R⁷ are isopropyl, R, R¹,R², R⁴ and R⁵ are hydrogen and R³ is --CH═CH₂.
 5. A lubricatingcomposition of claim 1 which comprises from 0.1 to 10 percent by weightof the additive compound.
 6. A concentrate for addition to a lubricatingcomposition, said concentrate comprising a minor amount of a mineral orsynthetic oil and a major amount of a compound having the generalformula: ##STR8## wherein: a. each of R, R² and R⁴ when taken singly isa hydrogen atom, an alkyl group containing from 1 to about 15 carbonatoms, an aryl group containing from 6 to about 15 carbon atoms or acycloalkyl group containing from 4 to about 10 carbon atoms;b. each ofR¹ and R³ when taken singly is a hydrogen atom, an alkyl groupcontaining from 1 to about 15 carbon atoms; an aryl group containingfrom 6 about 15 carbon atoms; a cycloalkyl group containing from 4 toabout 10 carbon atoms or an alkenyl group containing from 2 to about 10carbon atoms or R¹ and R³ taken together form the group --CHYCY═CY-- inwhich Y is a hydrogen atom or a methyl group or R¹ together with R² forman alkylidene group containing from 1 to about 6 carbon atoms; c. R⁵ isa hydrogen atom or an alkyl group containing from 1 to about 15 carbonatoms; d. R⁶ is an organic radical selected from an alkyl group, analkenyl group, an aryl group or an aralkyl group in which the alkyl oralkenyl groups contain up to 32 carbon atoms and the aryl or aralkylgroups contain up to 15 carbon atoms each; and e. R⁷ is hydrogen or anorganic radical selected from an alkyl group or alkenyl group, an arylor aralkyl group in which the alkyl or alkenyl groups contain up to 32carbon atoms and the aryl or aralkyl groups contain up to 15 carbonatoms each.
 7. A concentrate according to claim 6 compound (A) is acompound in which R⁶ and R⁷ are n-butyl and R, R¹, R², R³, R⁴ and R⁵ arehydrogen.
 8. A concentrate according to claim 6 wherein compound (A) isa compound in which R⁶ and R⁷ are n-butyl, R, R², R⁴ and R⁵ are hydrogenand R¹ and R³ taken together form the group --CH₂ CH═CH--.
 9. Aconcentrate according to claim 6 wherein compound (A) is a compound inwhich R⁶ and R⁷ are isopropyl, R, R¹, R², R⁴ and R⁵ are hydrogen and R³is --CH═CH₂.